The public safety community is about to embark on the most important upgrade to its mission-­‐critical communications systems ever. Today, police, sheriff, fire, and EMS personnel

only have access to voice communications on dedicated public safety spectrum. However, since the Federal Government allocated this spectrum for public safety use over the course of many years, it is not contiguous in nature but available on six

different portions of the wireless spectrum.

The voice channels on each of these portions of the spectrum allocated to public safety communications voice are not sufficient to provide communications for all of the agencies

and,

therefore, over the years, some agencies make use

of one portion of the spectrum while

other agencies are assigned channels

on another portion of the spectrum. This has resulted in a lack of interoperability between agencies, even within the same jurisdiction. It is not unusual for the police

department in a city to be on a different portion of the spectrum than the fire and EMS departments. The result of this is that when these agencies are working side-­‐by-­‐side on an incident they cannot directly communicate with each other.

In addition, since these channels are suitable for voice communications only, the public safety community has little or no access to data services, pictures,

or video. In order to partially solve some of these problems,

some departments have entered into service agreements

with commercial wireless operators for wireless phone, messaging, and broadband services. However, during major incidents these commercial networks are jammed with news media and citizens trying to contact their offices or loved ones. At the time this capability is needed most by the first responder community, it becomes unavailable due to commercial network overload.

The lack of interoperability that

has been an issue for public safety nationwide for more than three

decades was brought to the nation’s attention during the terrorist attacks on 9/11 and again during Katrina. A

number of different agencies all responded to provide services and were unable to coordinate with each other due to a lack of interoperable voice communications along with the lack of data and video communications. Since these incidents,

many agencies have upgraded their voice communications systems and

banded together to form regional and even statewide voice communications systems. However, because of the nature of their spectrum allocations

they

have not been able to address the issue of providing broadband communications services to those in the field.

Recently, Congress and the FCC allocated additional spectrum for public safety in what is known as the 700-­‐MHz band. This band was occupied by TV stations above channel 53 that were relocated lower in the TV spectrum. The resulting band was divided into blocks. Public safety received two blocks of this spectrum: one for additional voice channels and one for a nationwide, fully interoperable broadband system that

will add data, picture, and video capabilities for first responders.

AT&T, Verizon,

and others were then permitted to bid on other blocks within this band. The block adjacent

to the public safety allocation known as the D Block was supposed to have been sold at auction with the condition that the winner would work with public safety to build out a nationwide private/public partnership system that

would result in a shared network for both the private network operator and for public safety.

4

Cornerstone LTE Network Capacity Test Results

For a number of reasons,

no bids were received for this spectrum, thus

it was not auctioned. Today it sits idle. The public safety community quickly rallied and joined forces in order to convince both the FCC and Congress that the D Block should be reallocated to public safety so the amount of broadband spectrum available meets

the needs of the public safety community on a daily basis. During the

past two years, public safety has gained a lot of traction for this reallocation of the D Block but has also faced some stiff opposition from those who would like to see it re-­‐auctioned for commercial

purposes. Most of the discussions about who should gain access to the D Block have

to do with how much broadband spectrum public safety really needs on a daily basis for local incidents. There have been many studies (all theoretical in nature)

about the capacity of the existing public safety spectrum but until now there have been no real-­‐world tests to validate whether

the Public Safety Spectrum Trust (PSST) spectrum is really sufficient for public safety’s

daily requirements.

While this debate continues,

the FCC issued

waivers to 21 jurisdictions

allowing them to start building their portion of the network. The San Francisco Bay Area

applied for and received one of the waivers. The East Bay Regional Communications System Authority in partnership with the Bay Area Urban Area Security Initiative (UASI) developed Project Cornerstone as a proof of concept for the larger LTE network planned for the Bay Area. For the first time, we were able to conduct real-­‐world testing of the first demonstration system of public safety broadband. The methodology and the test results are presented in the following report.

The conclusion reached by Andrew Seybold, Inc.

as a result of this in-­‐depth

testing is that the presently allocated 10 MHz of spectrum (5

MHz by 5 MHz) for public safety’s exclusive use is not sufficient to meet its

needs on a daily basis. One of the prime advantages to implementing a nationwide broadband network is to enable first responders in the field to have access to video for the first time. Think of this as giving sight to the blind. For the first time,

those responding to incidents will be able to see video from a fixed camera near the incident. For the first time,

those in the command center in charge of an incident will be able to

view, in real time, video sent back from the scene. The SWAT

commander will be able to see exactly what his team’s sharpshooters can see using their rifle scopes, and during a bomb incident, live video of the bomb can be made available to bomb experts anywhere in the world, one of whom might recognize it and be able to guide those at the scene as to the best way to disarm it and render it harmless.

In order to accomplish all of this and more, including

having access to

information regarding an incident, the history of the perpetrator, or perhaps still pictures of a suspect wanted for

a crime, public safety needs sufficient bandwidth for this nationwide broadband system and as our test results conclusively

show, the 10 MHz of spectrum presently allocated to public safety does not provide sufficient

bandwidth for incidents that

occur in cities and counties on a daily basis. Therefore, the 700-­‐MHz spectrum known as the D Block needs to be reallocated to public safety to ensure it has the bandwidth it

needs.

Andrew M. Seybold

Robert O’Hara

CEO and Principal Consultant

Partner

Andrew Seybold, Inc.

Andrew Seybold, Inc.

5

Cornerstone LTE Network Capacity Test Results

Introduction

Andrew Seybold, Inc. (ASI) was contracted by the East Bay Regional Communications System Authority (EBRCSA) to undertake a series of network capacity tests for the first 700-­‐MHz system in the United States to deploy LTE. This network operates in 10 MHz (5

MHz by 5 MHz) of spectrum licensed

to the Public Safety Spectrum Trust (PSST) and under a waiver granted to EBRCSA by the FCC.

EBRCSA, in turn,

will be integrated with the planned nationwide fully interoperable broadband network dedicated to public safety and providing, for the first time, a nationwide public safety network based on commercial standards that

will enable

the first responder community to move equipment and manpower anywhere in the nation

and be able to communicate with all of the other agencies involved in a major incident. The lack of interoperability for public safety agencies has created problems during major incidents for more than thirty

years but was brought to the attention of the public during the Oklahoma City bombing, the 9/11 tragedy, and major hurricanes such as Katrina.

The reason for the engagement of ASI to perform capacity tests on this

system was many fold: First, it is important for network planning purposes to understand both the capacity and the limitations of the network. Next, there are ongoing discussions about the amount of spectrum, and therefore the amount of capacity the

public safety community needs on a daily basis. The public safety community and its

supporters believe that 10 MHz of broadband spectrum is not sufficient for the types of broadband services that

will be required on a daily basis,

especially in major metropolitan areas. There are also those who believe that the D Block, the additional 10 MHz of spectrum being requested,

should instead be auctioned for use by a commercial network operator.

Up to this point, all of the capacity models that

have been run by those involved with the public safety community have indicated that 10 MHz of spectrum is not sufficient for normal daily data and video requirements while those who are in favor of auctioning the D Block have presented their own capacity models that

are designed to support their own position. These

tests conducted on the Cornerstone system are the first real-­‐world tests conducted on

a live system,

and simulating a variety of incidents that are commonplace and handled, on a daily basis, by police, fire and EMS agencies either acting alone or in combination with the other agencies.

ASI has been involved in these discussions and Andrew M. Seybold has filed numerous comments with the FCC based on our own computer-­‐generated capacity studies. We found what we believe to be a major discrepancy in the way capacity was measured in the case of those who are proponents of the D Block auction. The capacity calculations used by these companies and the FCC were

based on capacity models developed by the 3GPP and were

based on a grid of 19 cells sites, each with 3 sectors,

for a total of 57 cell sectors. Interference was

assumed to be equal across all of these cell sectors and the capacity measurements were

based on spreading a user base across all of the sectors. While this capacity

6

Cornerstone LTE Network Capacity Test Results

modeling method may in fact work for commercial network deployments,

it is not germane when running capacity studies for a public safety broadband system.

The public safety community—police, fire, and EMS—responds

to multiple incidents per day within their own jurisdictions that involve multiple public safety responders. These incidents, for the most part, are confined to a small geographic area that will usually be provided coverage by only one or at the most two cell sectors of the LTE broadband network. Therefore,

the most important measure of capacity for a public safety broadband system needs to be focused on the capacity within a single cell sector rather than over a broader area. The testing methodology developed by ASI was based on

self-­‐contained incidents confined to a small geographic

area and modeled based on real-­‐world incidents that

the public safety community responds to every day.

As an incident grows in complexity the number of first responders on the

scene increases rapidly

and the amount of video and data resources needed to manage the incident will increase exponentially. Incidents can grow in size and complexity quickly. During

the

early stages,

while there is an incident commander on the scene, the demands that will be placed on the broadband network will continue to expand. If the incident needs to be managed for a longer period of time, additional resources such as command-­‐and-­‐control vehicles and incident management personnel will be put into

place. At this point, it

will be possible to manage the demand for voice, data, and video services, but in the early stages of an incident, those who are responding are occupied with sizing up the incident, deploying personnel, ensuring that the general public is out of harm’s way,

and coordinating resources that

are either on the scene or responding to it.

As an incident builds,

so too will the demand placed on the LTE broadband network, and since the vast majority of these incidents will occur within a small geographic area, the coverage of that area will, in most cases, be provided by a single cell sector or two overlapping cell sectors. Further, it is important to understand that a blocked call or lack of available bandwidth during the incident

as it grows in size and complexity

is not an option for public safety. Therefore,

the total amount of bandwidth available within a single cell sector is of paramount importance when designing the public safety broadband network and the amount of capacity available within each cell sector is directly proportional to the amount of bandwidth available within the cell sector. It is

imperative that there be enough bandwidth available to handle the increased demand in service on a daily basis.

Based on our testing and the resources public safety

agencies have identified as required for these types of incidents, ASI has concluded that 10 MHz of broadband spectrum (5 MHz X 5 MHz) is not sufficient to meet the needs of the public safety community on a daily basis in metropolitan and suburban areas of the United States.

The Network Under Test

The LTE network under test is located in Alameda County, California. The Evolved Packet Core (EPC) that

is used to manage the network, identify units on the network, and for all command-­‐and-­‐control

7

Cornerstone LTE Network Capacity Test Results

functions is located in the Alameda County Emergency Operations Center (EOC).

The EPC is connected to the two cell sites via County Microwave with a total per cell site capacity of 30 Mbits per second. For the purposes of these

tests,

the test server was co-­‐located at the Core in order to ensure that there were no network bottlenecks between the test server and the network under test.

This is a diagram of the Alameda County test network:

Each of the two active cell sites is

divided into three sectors,

which is the standard cell site configuration for all commercial cellular networks. For the purposes of these

tests,

all were conducted within the coverage of a single cell sector for each of the two sites and it was verified that there was no network traffic on the other two sectors. The total backhaul of 30 Mbits per second

provided by the County Microwave system was available for the single sector under test.

The field devices we used were Panasonic Toughbook computers of the same variety that

are in daily use within

the public safety community, and the LTE field devices were standard LTE USB modems that

were connected to the Toughbooks with USB cables. These USB modems were connected to two unity gain antennas mounted on the roofs of the test vehicles,

providing the best case connectivity between the user device and the network (units with internal antennas such as handheld LTE devices when available will have degraded coverage and capabilities).

8

Cornerstone LTE Network Capacity Test Results

Additional network details may be found in Appendix A. The network was functional and fully operational and drive tests were conducted both by Motorola and Anritsu prior to beginning the testing. Stationary tests were conducted at multiple locations, run multiple times for verification, and the results are presented later in this report.

The Test Procedures

The test methodology developed by ASI for these capacity tests are based on real-­‐world scenarios. That is, typical incidents that require public safety response on a daily basis. The incidents were created by ASI with the assistance of public safety officials from various

police, fire, and EMS departments across the nation. They

are based first on the amount of manpower and the number of units needed to respond to each of the various types of incidents and then the stated requirements in terms of video and data traffic public safety officials believe would be required for each incident. The incidents were developed using the Incident Command Structure (ICS),

The tests were designed around each of these incidents and the number of personnel from each agency was vetted by several departments across the country. The data and video requirements for each incident were calculated to provide uplink video to the dispatch center from the first unit

on scene. This would then be retransmitted down to additional incoming resources including the ranking officer who responds

to take command of the scene.

A video was recorded in the test area, streaming

at a resolution and data rate comparable to those used in police patrol cars. Streaming software and measurement software were

loaded onto both the server computer and each of the client computers. Scripts were written to calculate

actual throughput, accuracy of reception, and other factors. Video files were created

for both uplink (from the scene) and

9

Cornerstone LTE Network Capacity Test Results

downlink (to the scene and responding units)

and were

varied in capacity requirements based on the resolution of the video required by public safety.

Prior to and during the stationary tests, both Motorola and Anritsu personnel conducted drive tests of the cell sector coverage area to verify coverage of the cell sector in use during the tests. During the actual tests,

and recording the amount of both the uplink and downlink traffic being generated during the tests.

More details of

the testing methodology and the testing software used are provided in Appendix B.

The Actual Tests

The main objective of

the tests was to measure network capacity in both the uplink and downlink directions from the scene of an incident and at various distances from the center of the cell sector under test. Four locations were chosen for each cell sector under test:

1.

Near the cell center (highest possible data rates) location was 0.5 miles from the cell center

2.

Mid-­‐coverage (lower average data rates) location

was 1.5 miles from cell center

3.

Edge of cell (lowest average data rates) location was 3.8 miles from the cell center

4.

A final location at the very edge of the cell coverage,

in this case

4.2 miles from the cell center

5.

The terrain varied for the two cell sectors under test

a.

One cell sector was located within

the City of Martinez in a semi-­‐dense building environment,

but most of the buildings while multi-­‐story were not more than six to eight floors tall

b.

The second location was more suburban in nature on the edge of Martinez with sparse housing, large trees, and in one case in the parking lot of a large shopping center.

It should be noted that LTE broadband networks are designed to provide three different data speeds down to the devices and two different data rates from the devices up to the network. Basically,

those closest to the cell site will have the fastest data speeds to and from the network, those located in the middle of the cell sector coverage will have the next fastest data speed down from the network and,

depending upon their location, either of the two up-­‐to-­‐the-­‐network data speeds. Those toward the edge of the cell sector will have access to the slowest outbound data speed and the slower of the two up-­‐to-­‐the-­‐network data speeds.

10

Cornerstone LTE Network Capacity Test Results

Devices and Configurations

The devices used for field testing were USB LTE modems built and designed specifically

to provide service within the public safety licensed spectrum. In most cases,

during the actual tests these modems were connected via USB

cables to the Panasonic Toughbooks

and external unity gain antennas on magnetic mounts were placed on the roof and/or back deck of the test vehicles. Two antennas were connected to each modem.

Seven Panasonic Toughbooks with Windows XP were used for all of the testing

For

several of the tests,

the USB modems made use of external antennas but were located within the vehicle rather than roof-­‐mounted. This provided us with a sample of lower performance devices as well as the optimum performance of the modems using external antennas.

One of the test modems

For the most part, the modems performed well. There were several times during the tests when the modems stopped working due to glitches within the modem and the tests were stopped and restarted multiple times

to verify all

of the results. However, as can be seen from the data in Appendices

C

and D, a few of the tests are reported using only a single test session. The test Toughbooks were placed in two

11

Cornerstone LTE Network Capacity Test Results

or three vehicles and the vehicles were placed within 50 to 300 feet of each other, simulating a number of devices within a confined location.

One of the test vehicles –

note the antennas on the roof

The actual testing started with a single video or data stream from the vehicle up to the server at the Alameda County EOC, followed by a simulation of a retransmission of the video down to the scene. During each test,

the number of video and/or data streams to and from the scene was increased. At the same time,

Anritsu was monitoring the LTE channel in both directions and was recording the percentage of the capacity in use during each phase of the testing. This gave us a visual indication of the percentage of capacity that

was being used during each phase of the testing. In addition,

the other criteria measured included the quality of the video in both directions and any packet loss experienced during the up and down loading of the data files. Appendix C shows the test results as recorded for both data and video up and downloading as well as the capacity usage as measured by Anritsu during the tests.

The tests were run multiple times except as noted above and the overall results are recapped in the next section of this report and in a detailed listing of the tests included in Appendices C

and D.

The test results reported were collected over several multi-­‐day test cycles, recorded on the server (uplink) and on each of the seven Panasonic Toughbooks

used for

testing (downlink). Anritsu’s data was captured in real time. Some of this data is included in the next section and some is included in Appendix

E as well. ASI is confident that these test results reflect real-­‐world scenarios and that the results are based on best case network performance with no known chokepoints between the mobile devices and the test server located within the core of the network.

12

Cornerstone LTE Network Capacity Test Results

Test Results

We first measured the total capacity of the cell site by sending data from it to the mobile units (downlink or download). We measured sending data to a single mobile unit and to several mobile units at the same time. Note that when we used multiple mobile units they were all located in the same cell sector. These tests were made under what should be considered “ideal” conditions: We were the only users of the network during the tests;

there was no other traffic.

As described in Appendix B, we tested at three different locations. The locations were selected to represent “best case”

(near the cell tower), “typical case”

(a midpoint in the cell coverage area), and “worst case” (at the cell edge) network coverage and performance. We sent random data to and from the mobile units using the same network protocols that streaming video cameras use. From these tests we arrived at the following measurements of the

network’s total available bandwidth for a single sector:

Test Site

Downlink Bandwidth

Uplink Bandwidth

Glacier Street (near cell)

16 to 19 Mbits / sec

6 to 7 Mbits / sec

Sunvalley Mall (mid cell)

11 to 15 Mbits / sec

2 Mbits / sec

John Muir House (cell

edge)

6 to 8 Mbits / sec

0.2 to 0.3 Mbits / sec

These measurements were made streaming data to and from a single or at most a handful of mobile units. As more mobile units are present in the cell sector, more network bandwidth will be devoted to packet management and other network traffic.

Diagram of

LTE Resource Blocks

LTE assigns resource blocks to

each user within a cell sector;

in a 5

MHz by 5 MHz network the total number of resource blocks available is 520. Some of these blocks are reserved for signaling

data

(16

13

Cornerstone LTE Network Capacity Test Results

blocks)

and network-­‐to-­‐device communications and are therefore not available for data communications.

The LTE carrier is made up of resource blocks. Some are reserved for signaling, but most of them are for data. Each user is assigned a number of resource blocks depending upon their priority on the system. The more data they are sending, the more resource blocks are required during their transmission. When sending a streaming video,

the system allocates as many resource blocks as it can to that user.

Resource blocks in use during the network testing, courtesy of Anritsu America

Resource blocks that

are not in use during these video transmissions are the signaling channel resource

blocks that

are used for the network and device to communicate

with each other. In this particular case, 100% of the available resource blocks are being occupied with data. The signal level being reported is very good.

Besides streaming random data to and from the mobile units, we also streamed actual video using an MPEG4 codec. We recorded a VGA quality (640 x 480 pixels at about 15 frames per second) video while driving around the streets of Martinez near the test locations. This quality is typical of video cameras currently installed in police cars. The captured video enabled

us to consistently stream a video with a known data rate of 1.91 Mbits per second.

14

Cornerstone LTE Network Capacity Test Results

At each of the test locations we simultaneously streamed videos to and from multiple mobile units while recording the received

videos. Below is an image from the test video:

It became very obvious when there was insufficient bandwidth for a video to display, as the image quickly froze and broke up as shown below:

15

Cornerstone LTE Network Capacity Test Results

Actual video playbacks will be

available in the PowerPoint presentation that

will accompany

this report and at www.andrewseybold.com.

The table below shows the number of simultaneous videos we were able to successfully stream to or from the cell site. Note that at the John Muir House location, which is

at the edge of cell coverage, we were unable to stream a single video from the mobile unit to the cell site. This confirms the data measurements presented above, as we only measured an uplink bandwidth of 0.2 to 0.3 Mbits per second at that location, which is clearly below the 1.91 Mbits per second needed for the test video to successfully stream.

Test Site

Downlink Video Streams

Uplink Video Streams

Glacier Street (near cell)

5

3

Sunvalley Mall (mid cell)

3

2

John Muir House (cell edge)

2

0

More information on the data test results can be found in Appendix C. More information on the video test results can be found in Appendix D. We interpret the above numbers in the next section.

Perhaps the best way to interpret the test results is to walk through two scenarios where first responders are reacting to an incident. We are not describing these incidents as they happen today, but as we project they will occur in the future when public safety LTE networks are widely deployed. The obvious change from today will be a significant increase in the use of live video feeds as a real-­‐time information gathering tool for the first responders. The two scenarios are:

•

“Barricaded Hostage”: a gunman holds one

or more hostages in a building

•

“Suspected Bomb”: a suspicious package turns out to be

a bomb and must be deactivated

In each of these scenarios there will be a variety of data traffic both up to and down from the LTE network. Not every source will be

active at all times. Data traffic will be transmitted from devices such as these in the field:

all video feeds from the field are transmitted to the central dispatch center where the dispatcher relays one or more selected feeds to the police incident commander, the SWAT commander, and the fire chief. Therefore,

in addition to the above traffic, the following data

traffic will be transmitted down to devices in the field from the LTE network:

•

Video feeds from any of the sources listed above, in either high resolution or converted down to a lower resolution

•

Video feeds from existing wired street or highway cameras

•

Video feeds from third-­‐party cameras such as news helicopters

•

Downloads of building plans, utility network plans, photographs, or other data

Beyond the above traffic related to the incident, there will be ongoing data traffic (both up and down) related to normal police activity in the same cell sector. An example of this would be

a

license check arising from a traffic stop.

What is important to this report is the estimated data traffic at the peak of the incident. Of course,

in real life such incidents unfold

over time. We are interested in projecting whether the LTE network can handle the maximum data load each scenario will generate.

Barricaded Hostage

A gunman holds one or more hostages in a building for a period of hours. The police respond with the following mobile units:

17

Cornerstone LTE Network Capacity Test Results

•

2 snipers

•

1 helicopter

•

1 police incident commander

•

1 SWAT commander

•

1 police car camera

•

2 police vehicles receiving video feed

At the peak of the incident, we have the following data being uploaded to the LTE network:

•

Sniper 1 high-­‐resolution streaming video: 3.1Mbits per second

•

Sniper 2 low-­‐resolution streaming video: 1.2 Mbits per second

•

Police car camera streaming video: 1.9 Mbits per second

•

“Background” ongoing police activity: 0.1 Mbits per second

This gives us a 6.3 Mbits per second uplink data stream to the LTE network and over the backhaul to the command center. We assume that the command center relays the sniper streams (one at high resolution and one at low resolution) and the helicopter stream to both the police and SWAT commanders, and the police car video stream to each of

two close-­‐in police vehicles. This means the following data are downloaded over the LTE network:

This gives us a 19.2 Mbits per second downlink data stream from the command center over the backhaul and down the LTE network. The total backhaul load imposed by these streaming video feeds is 25.5 Mbits per second. Note that the downloads of floor plans or other data requests are probably only a few megabytes each and would only last 10 or 20 seconds.

18

Cornerstone LTE Network Capacity Test Results

The following diagram illustrates

both the projected bandwidth required for the incident and the bandwidth that is available on a 10 MHz (5

MHz by 5

MHz)

system. Where the available bandwidth is inadequate it is highlighted in red

(below the line indicating

required bandwidth):

Barricaded hostage scenario bandwidth as measured and required

It should be obvious that this scenario exceeds the capabilities of the network we tested

in almost every situation.

19

Cornerstone LTE Network Capacity Test Results

Suspected Bomb

A suspicious package turns out to be a bomb and must be deactivated. The bomb squad uses a remote-­‐controlled robot to open the package and deactivate the explosive device.

Civilian cellular telephone service is turned off in the area to foil remote activation. The police respond with the following mobile units:

•

1 helicopter

•

1 police incident commander

•

1 bomb squad commander

•

1 bomb squad remote control camera

•

1 police car camera

•

1 police vehicle receiving video feed

At the peak of the incident, we have the following data being uploaded to the LTE network:

•

Bomb

squad remote control high-­‐resolution streaming video: 3.1

Mbits per second

•

Police car low-­‐resolution streaming video: 1.2 Mbits per second

•

“Background” ongoing police activity: 0.1 Mbits per second

This gives us a 4.4 Mbits per second uplink data stream to the LTE network and over the backhaul to the command center. We assume that the command center relays the helicopter stream, bomb squad remote control camera stream,

and police vehicle stream to the bomb squad commander;

the helicopter and squad car

stream to the police commander;

and the helicopter stream

to a close-­‐in police vehicle. This means the following data are downloaded over the LTE network:

Mbits per second downlink data stream from the command center over the backhaul and down the LTE network. The total backhaul load imposed by these streaming video feeds is 17.9 Mbits per second. Note that the downloads of utility plans or other data requests are probably only a few megabytes each and would only last 10 or 20 seconds.

20

Cornerstone LTE Network Capacity Test Results

The following diagram illustrates

both the

projected bandwidth required for the incident and the bandwidth that

is available on a 10 MHz (5

MHz by 5

MHz) system.

Again, where the available bandwidth is inadequate it is highlighted in red

(below the line indicating required bandwidth):

Suspected bomb scenario bandwidth as measured and required

It is clear that the test network can only support this scenario if it occurs very close to the cell site.

Public Safety Video and Data Requirements

The above scenarios do not account for any other types of applications that

may be used or needed during these incidents but they clearly show that even under these conditions the 10 MHz of spectrum allocated to public safety is not sufficient to provide the video and data services that

will be required during these types of incidents. These incidents are not events that

happen once in a while within a given jurisdiction, these and other incidents that require multiple-­‐unit response and the use of video and data for extended periods of time occur on a daily basis.

21

Cornerstone LTE Network Capacity Test Results

Note that the above scenarios do not include any voice

service over LTE.

If and when mission-­‐critical voice does become available over LTE it will put additional stress on the broadband network,

especially in confined areas,

which is the case for most incidents. If we had added the bandwidth required for 30 push-­‐to-­‐talk devices into our

testing scenarios, the amount of available bandwidth for video and data services would be reduced by 15-­‐20% (based on current estimates within

the LTE technology community). Thus the public safety network needs to have enough spectrum available to be able to provide the types of video and data services required as well as to be able to add mission-­‐critical voice services if they become available.

Public demand for broadband services has grown more than 75% each year for the past

three years, yet if you had asked

prior to commercial broadband being available what the demand for wireless broadband services would be, the answer, three

years ago,

would not have anticipated this huge rate of growth due to the advancement of smartphones and tablets as well as the proliferation of applications. This same growth curve will apply to the public safety community as well. Until the network is built and placed into operation we can only identify the most obvious of applications and services. However, once the network is online, just as in the commercial world, public safety will find additional uses and applications for the broadband network that

will not only drive up daily demand and usage but also drive up the amount of bandwidth that

will be consumed during these types of incidents. Therefore,

to limit the public safety community to 10 MHz of broadband spectrum will not meet its

needs on a daily basis nor will it allow

for new and innovative applications that

can be used to better serve the pubic and protect the lives of first responders

as well.

What Public Safety Can Count On in 10 MHz of Spectrum

As described above,

the tests were conducted with the minimum expected response to an incident. As incidents

escalate,

response levels

will

increase and the demand for data and video services will increase as well. As can be seen by the test results,

additional demand would create network overload in every condition and at every location within a cell sector.

During a major incident, once an incident command center has been established it will be possible to interactively manage the demand for data and video,

but the demand will outstrip the network’s ability to meet that demand. Well before an incident command post is established at the scene,

the demand for data services will be such that the network will quickly reach saturation and become non-­‐functional. As we observed,

when the network is overloaded,

the impact of the overload was not only

to block the subsequent video or data stream but also to cause the videos or data streams

that

had been usable to become unusable.

Public safety will be able to rely on a 10-­‐MHz network during the initial phase of the incident and perhaps again once a command

structure has been established. However, during the most critical portion of the response as more first responders

arrive on the scene and when the agency’s command center is in an information gathering mode,

the system will reach saturation and not be able to provide the critical data needed to contain the incident. Incidents can and do grow rapidly in size and

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Cornerstone LTE Network Capacity Test Results

complexity, and it is crucial to those in the field as well as those within the command structure to have real-­‐time video and data services available to them during

the entire incident, not only

at the beginning.

How Much Spectrum Is Required?

As described above,

the tests

demonstrate that 10 MHz of spectrum is inadequate to support the needs of the public safety community. The obvious question then is if 10 MHz is too little, how much is enough? While we do not have a 20-­‐MHz network to test, we can project its performance. The following diagram illustrates how 20 MHz of contiguous spectrum would perform in the barricaded hostage scenario. Again, where the available bandwidth is inadequate it

is highlighted in red (below the line indicating required bandwidth):

Barricaded hostage scenario bandwidth as projected and required

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Cornerstone LTE Network Capacity Test Results

The projected 20 MHz (10

MHz by 10 MHz) network has sufficient capacity for this demanding scenario in all locations except at the very edge of the cell sector coverage.

Edge of cell communications is an issue with both commercial and public safety networks. It will be critical for the network to be designed to minimize the edge of cell situations within a given coverage area. This can be accomplished with overlapping cell coverage but at the same time care must be taken to minimize the interference between overlapping cells. After the initial network completion it will be necessary to drive test the network to ensure that

sufficient bandwidth is available, especially within major metro areas. Ensuring that there is sufficient bandwidth could add to the overall cost of this network.

The following diagram illustrates how 20 MHz of contiguous spectrum would perform in the suspected bomb scenario:

Suspected bomb scenario bandwidth as projected and required

The 20 MHz (10

MHz by 10

MHz) network has sufficient capacity for this demanding scenario in all locations except at the very edge of the cell sector coverage, and that for uplink only.

Again, system design will be critical to ensure that edge of cell situations are minimized whenever possible.

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Cornerstone LTE Network Capacity Test Results

Conclusions

We believe that the tests conducted using the Cornerstone network provide the first real-­‐world results for a 10-­‐MHz public safety broadband system.

After vetting the incidents chosen prior to the testing and vetting the results of the testing with seasoned first responders and commanders,

it is clear to us that 10 MHz of spectrum will not meet the daily incident requirements of the public safety community.

Some detractors might try to

point out that some broadband is better than none. However, this is not the case since at the most crucial times network overload can and does result in the entire system not being available for use. During the recent earthquake on the east coast,

the commercial networks were fully operational but

they were overloaded. The result was not only

that those who wanted to make a call or

send video were denied access to the network,

but many who had network connectivity lost that connectivity—a situation that

is intolerable for public safety.

The public safety voice networks are built to meet harsh standards, and the broadband network must be designed and built to those same mission-­‐critical standards. Not having enough capacity available for the network is not an acceptable option. Neither is expecting the commercial operators to provide priority access to the first responder community. Again, during the east coast earthquake not only were the networks overloaded, the signaling channel used by devices

to communicate their requests

for service was overloaded. In that circumstance,

even if priority had been granted to public safety,

the

devices would not have been able to communicate that priority status with the network and would not have had access to the network.

Public safety needs a dedicated, nationwide broadband network. The network must be robust and it must have sufficient

bandwidth available within a single cell sector. Our findings clearly show that 10 MHz of spectrum and the bandwidth it provides does not meet these criteria. More spectrum is

needed and it must be contiguous to the existing public safety broadband spectrum, not in some other portion of the spectrum and not allocated after the public safety broadband network is in operation. To add spectrum that

is not adjacent

to the existing broadband spectrum would

more than double the cost of the network and would

increase the cost of the devices used on the network.

Based on these real-­‐world tests,

we strongly recommend that public safety be provided with at least 20 MHz of contiguous spectrum (10 MHz by

10 MHz). The only way to accomplish this is to reallocate the 700-­‐MHz D Block to public safety and this should be done prior to the build-­‐out of the waiver recipients’

portion of the nationwide network. The cost to build out 10 MHz of spectrum and 20 MHz of spectrum is identical at the time of construction. Later,

the addition of this spectrum would

add to the cost of the network and require device redesign,

adding to the cost of the user equipment. The entire premise of providing public safety with broadband spectrum using a commercial technology is to provide public safety personnel

with capabilities they do not have presently at a lower cost than its

existing voice communications equipment.

The public safety nationwide interoperable broadband network based on 10 MHz of spectrum that

is currently available will not meet the needs of the public safety community. Rather it will, on a daily

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Cornerstone LTE Network Capacity Test Results

basis, end up congested at incident locations and fail to provide the public safety

community with the bandwidth that is needed for data, pictures,

and video. Most emergency incidents are confined to a small geographic area and,

as noted above,

our testing results conclude that the current bandwidth assigned to public safety is not sufficient even for incidents that

occur on a daily basis.

If, in the future, mission-­‐critical voice is

added to this network,

it will further degrade the amount of available bandwidth. The demand for voice, data, and video all within the same cell sector will swamp the network’s capacity and even with Quality of Service and priority status enabled, the public safety community will not have enough bandwidth to provide the mission-­‐critical level of service required. Public safety cannot afford to rely on a network that

will not provide the amount of bandwidth it

needs

when it

needs

it. We therefore recommend that the additional 10 MHz of bandwidth that

is adjacent to the public safety spectrum be reallocated to public safety in a timely manner.

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Cornerstone LTE Network Capacity Test Results

Appendix A: Network Details

The network under test was configured in this manner:

Motorola, the network system supplier, stated that the network was configured with a 30-­‐Mbps backhaul bandwidth:

•

Not limited to eNodeB

sector

or user device

•

Available on a first come, first served basis

•

Full 30 Mbps can be assigned to a single user device

The bottom line

is that the backhaul did not create a network chokepoint. Also, note that none of the tests transmitted data over the Internet.

The cell site power output and effective radiated power are as follows:

•

Full power output of the system is 80

Watts (2

x

40

Watts max) and the corresponding ERP (with conservative estimates on line losses) is 56.9dBm

27

Cornerstone LTE Network Capacity Test Results

•

FCC Experimental License limits to 59.4 Watts max ERP. To abide by this limitation, the power on the eNb has been turned down to 10 Watts total, which corresponds to about 59.4 Watts ERP.

To explain further:

Tx Power = 10W = 40

dBm

Antenna Gain = 14

dBi

Cable + Connectors Loss = 4

dB*

EIRP = 40 + 14–

4 = 50

dBm

ERP = EIRP–

2.1dB = 47.9

dBm

This is almost right at the FCC Experimental License ERP limit of 59.4W = 10*log10(59.4x1000) = 47.7dBm.

At the Glacier Street site, pictured below, the LTE antennas (circled) are co-­‐located on a tower hosting public cellular antennas as well as microwave antennas:

LTE Antenna location at the Glacier Street site

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Cornerstone LTE Network Capacity Test Results

In downtown Martinez at 651 Pine Street the LTE antennas are located on top of the tallest building in the area:

LTE Antennas at 651 Pine Street

The network core and our test server were located at the Contra County Emergency Operations Center:

Microwave dishes at EOC network core and test server location

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Cornerstone LTE Network Capacity Test Results

Appendix B: Testing Methodology

Test Locations

We tested at three different sites in the Martinez, California area. The Glacier Street site was adjacent to the LTE base station at the center of the cell sector; our test location was 0.1 miles from the base station. This gave us the best possible signal strength, and thus the maximum data throughput over the